Bai Mengyao is an immortal who cultivated for over a thousand years in the Immortal Pool before ascending, but her timing seems to have been terrible. At that time, a demon king ruled the world. His demonic power was boundless, he slaughtered the innocent, and no one could destroy him. As long as his demonic soul survived, he would be reborn without limit, growing stronger with every rebirth. Who could possibly defeat him? Before long, demons had nearly wiped out humanity and the immortals across all three realms. With nowhere left to turn, the immortals exhausted their lifelong cultivation to cast a divination. They discovered a glimmer of hope: the demon king could still be stopped at the moment of his birth, a thousand years in the past. Overjoyed, they concluded that Bai Mengyao was the ideal candidate. Thus, she followed the will of Heaven back a thousand years, shouldering the mission of destroying the demon king's soul as she ventured into the mortal realm...
What she doesn't know is that her arrival is a gift from Heaven to him, but also his calamity. He can't overcome it, and he doesn't want to.